Pressure discharge containers

ABSTRACT

Means for use in discharging powder materials from containers, particularly bulk transport vehicles in which a pressure-operated valve is provided in the base of the vehicle for admitting air or other gas to the container so that the material is aerated at or adjacent the discharge outlet.

United States Patent [56] References Cited UNITED STATES PATENTS [72] Inventor Ralph Murfltt Wlsbeeh, England Wi n m m m mfl nd o mmam .mo deopmn LLAKKRSA 49589 46 05663456 99999999 mvmmwmw 6 7308 6 03540379 2 333 .3 95337549 4-294588 ,J 2332223 lmwv 7 n .m

9 r6 9%M l In m t 81M I l I h 5""- u 9 7AJRWAG3 0. de mm m Id 8 p .l mm m AFPA P Una nu l 224- 333 [iii ill Primary ExaminerAndres H. Nielsen Attorney-Baldwin, Wight & Brown [54] PRESSURE DISCHARGE CONTAINERS 8 Claims, 8 Drawing Flgp.

[$2] [1.8. 302/53, ABSTRACT: Means for use in discharging powder materials from containers, particularly bulk transport vehicles in which a pressure-operated valve is provided in the base of the vehicle for admitting air or other gas to the container so that the material is aerated at or adjacent the discharge outlet.

302/52 [5i] llll. B653 53/40 PATENTEU JUL 1 3 WI SHEET 3 BF 3 rs Discusses comm This invention relates to containers for transport in bulk of powdered materials.

When handling powdered and other finely divided materials in bulk, particularly cement, in order to facilitate discharge of the contents of the container under pressure it has been general practice for a number of years to effect discharge by aerating the material by providing at or adjacent the discharge outlet an air permeable deck. Thus in mobile containers for cement, the container or so-called tanlt in addition to provision for tipping it, is equipped with a blower for feeding air under pressure to a porous pad in the base, provision also being made for venting pressurized fluid or air from the interior of the tank into the discharge pipe or passage to facilitate the through flow of fluid-powder in the discharge pipe.

We have now found that a more satisfactory method of introducing air to the container in order to pressurize its contents is by means of a valve-controlled inlet, thereby clirninating the use of an air permeable pad or deck, with its inherent disadvantage of clogging of the pad which sometimes occurs.

According to the present invention means for evacuating powder material from a container comprises the combination of a discharge outlet in the base of the container at one end or side thereof and a one-way pressure operated valve closing the end of a passage connected to a source of gas pressure and adapted, on opening under pressure. to discharge gas in sub stantially the entire area surrounding the valve.

In a preferred arrangement a poppet valve is provided in the base of the container adjacent the discharge outlet at the end of a pipe connected to a supply of gas under pressure, opening of the valve, which normally remains closed under the influence of gravity, being by gas pressure, and the lift of the valve being small in relation to the cross-sectionalarea of the valve opening.

The invention is illustrated in the accompanying drawings as applied to a transportable container for cement and coal dust. in which:

FIG. 1 is an elevation of the tipping body or container (the undercarriage being shown in dotted. lines) fitted with a discharge control means in accordance with the invention, the body being shown in its normal or travel position;

FIG. 2 is a sectional view on an enlarged scale showing the valve unit and FIG. 3 is an esploded view of the valve unit shown in FIG. 2;

FIGS. 4 ands are detail views of alternative forms of valve devices;

FIG. 6 is an elevation of a traileetype container unit fitted with a series of discharge outlets each having discharge control means in accordance with the invention;

FIG. 7 is a transverse section on the line VII-VII of FIG. 6, and

FIG. I is a detail view of the discharge control means of FIG. ,7.

Referring first to FIG. 1, there is shown a vehicle having a container 12in the form ofacylindrlcal tanli for the powdered material, the tank having a truncated conical end portion provided with a discharge nozzle 7, which is constructed in the form of a venturi and terminates in a fitting 8 for connection thereto of a pipeline. A hatch I l is provided at the top of the container I: for loading the material therein.

Provision is made for pressurizing the contents of the container I2 by means of a blower (not shown), the outlet being connected to a pressure line I, from which air under pressure is reieased directiy into the powder mass within the container 12 through one or multiple spaced. valved outlets as described below.

Release of the contents of the container I2 is by means of a slide or rotary plate sbutolt valve indicated at 12' by which the entry to the discharge nozzle 7 can be completely blanked off. this valve being operated to open and close by a hand control 10 from the exterior. Pressure from the interior of the cont'ainer 12 is transmitted by a pipeline 4 whose inletend opens into the upper air space of the container and which is connected at its other end through an air control valve 5 and an inlet section 6 opening into the discharge nozzle 7 upstream of the venturi throat.

In the embodiment illustrated admission of air to the bottom of the container is through an inlet opening controlled by a single poppet-type valve, indicated generally at 3, provided at the outlet of the pipe I which replaces the customary air permeable deck.

As can be seen from FIG. 3., the valve comprises a valve housing 13 having at its upper end a fixing flange 25 by which it is attached by welds to the tank wall. At its lower end is a locating flange 25 in which are holes 24 to receive fixing screws by which. when the flanged end 22 of pipe I is secured thereto, a valve lining or body 14 is located. The poppet valve comprises a valve head I9 and valve stem [8, the stem 18 being slidably carried in valve guides 17, which guides 17 are secured to the valve body 14 by spider arms [6. The lift of the valve 18, Le. its maximum distance of travel, is highly critical, for which purpose its movement is limited by lock nuts 21 adjustably secured to the lower end of the valve stem. The maximum lift of the valve is based upon the area of the inlet pipe and is such that the exhaust or air release area does not exceed 2.5 times the area of the gas supply inlet pipe or opening. It will be appreciated that the lift of the valve and thus the extent to which it opens should be sufficicnt tocnsure that overheating will not occur.

Thus an unnecessarily restricted opening or openings in relation tothe rate of flow in the or each supply pipe would generate an unacceptable rise in temperature in the incoming air with an adverse effect on the materials being handled. Too high an air speed at the point of release wouldnnoreover, adversely effect the desired aeration characteristics.

Furthermore, the location of the inlet and thus of the valve in relation to the discharge orifice is critical in that the minimum distance between the centerline of the valve orifice and the plane XX of the outlet cutoff plate should not be less than 3" whatever the capacity of the tank. The maximum distance should not be greater than 24" in the case of a tank up to I000 cubic feet capacity and not less than 24" per I000 cubic feet of total tank capacity.

While tests have shown that a poppet valve arrangement has salient advantages both in construction and operation, alternative forms of one-way pressure-operated valves are possible.

One such form of valve device is shown in FIG. 4 wherein a number of flaps 27 are mounted for pivotal movements about a central axis 28. In FIG. 4 the valve device comprises three valve flaps, the dotted lines showing the valve flaps in their open position. FIG. 5 shows a multisided valve having four flaps 29 but clearly a similar arrangement embodying a number of segments having either arcuatc or straight edges may be used.

- in large size containers an additional poppet or other valve controlled inlet may be introduced to assist the discharge in other areas of the tank.

Referring now to FIGS. 6, 7 and 8, there is shown a trailer unit comprising an undercarriage 30 mounted at its rear end on a bogey 3| and having a forward platform 32 for attachment to the towing vehicle.

In this embodiment the container is divided into a series of chambers or compartments by partition walls or baffles 33, each chamber so formed including a well 34 of inverted conical formation and terminating in inclined straight sided wall portions 35. 36. The one sidewall portion 36 incorporates a discharge outlet 37 having a discharge nozzle similar to the nozzle 7 and provided with a sliding or rotatable closure plate so that the nozzle can be completely blanked off, provision being made for admitting pressure air as shown in FIGS. I and 3 to assist discharge.

Associated with each discharge outlet 37 is a one way pressure operated poppet valve 38 valve 38 being mounted in a valve seating formed in an extension of the wall 35.

The elimination of the aeration pad allows the air to be used to a higher degree of effectiveness, with the result that the pressure required to produce aeration of and thus convey the materials is less, the airflow rate can also be lower and hence the horsepower required to operate the blower is reduced. In practice, tests have shown that using a 4" inlet pipeline and a poppet valve of 3" diameter the valve head or plate should be so positioned that its center line is not less than 3" from the discharge outlet cutoff plate and not substantially more than l2" from the plate per each 1000 cubic feet of total tank size, the preferred distance being 6".

The minimum and maximum opening movements of the valve as described above is determined by the size of the pipeline normally required to convey air from a compressor or blower, for example. when using 300 cfnr ofair it will be cal culated on a 3" pipeline. Based on a 3" pipe size, the minimum lift should be such as to give an opening area not less than 1.76 square inches and not exceeding [7.65 square inches, this measurement being the area through which free air can enter the pressure vessel.

While it is preferred to position the valve with its valve seating flush with the base of the tank, this is not essential and it may be slightly raised or slightly countersunk.

Tests have demonstrated that by restricting the valve move ment it results in the underside of the valve functioning as a baffle and thereby causing an upspread of air which results in aeration of the powder in the vicinity of the valve, the extent of aeration being dependent upon the valve displacement,

In contrast to the effect obtainable by an incoming jet of air, the provision of a valve enables the air to be diffused over the area surrounding the valve which not only supports but aerates the material above it, ie. its first action is to support the material by a cushion of air and the material, being of a finely divided nature, then becomes aerated and can flow into the discharge orifice.

The provision ofa valve controlled inlet for the air or other fluid has the further advantage that it enables discharge to be effectively carried out at relatively lower pressures and thus horsepower requirements. The valve as such is sturdy and its simplicity in design leads to further benefits in efficiency of operation and manufacturing costs and due to its simplicity it can readily be cleaned.

What l claim is:

1. Apparatus for discharging powdery material from a container comprising a container body having a bottom wall and an end wall in upstanding relationship thereto, said end wall having an outlet opening through which powdery material is adapted to be discharged from an interior of said container body, said bottom wall having an inlet opening adjacent and upstream of said outlet opening for introducing a pressurized gaseous medium into said container body interior for aerating said powdery material, gravity actuated reciprocal poppet valve means including a valve element having a valve head by which said inlet opening normally remains closed for selectively placing said inlet opening in fluid communication with the container body interior and fluid pressure means for displacing said valve head above said bottom wall whereby powdery material above said valve head is displaced vertically in order to break down any caking that may be present and following which displacement of powdery material the material so displaced and surrounding the valve opening is aerated by the gaseous medium to enable discharge of the material through the outlet opening.

2. The apparatus as defined in claim 1 including additional valve means for selectively opening and closing said outlet opening.

3. The apparatus as defined in claim 1 wherein said valve head is movable relative to a valve seat for opening and closing said inlet opening, and means for adjustably limiting the opening movement of said valve head in a direction away from said valve seat whereby the open area between said valve head and valve seat is relatively small in relationship to the area of said inle opening,

4. The: apparatus as defined in claim 1 wherein the distance between the center line of the valve means and the discharge outlet does not exceed 24 inches in container bodies of up to l ,000 cubic foot capacity.

5. The apparatus as defined in claim 1 wherein said outlet opening is in fluid communication with a discharge nozzle disposed exteriorly of said container body, and means are provided for introducing a pressurized fluid medium into said discharge nozzle to augment the flow of the powdery material therethrough.

6. The apparatus as defined in claim 1 wherein said outlet opening is in fluid communication with a discharge nozzle disposed exteriorly of said container body, means for introducing a pressurized fluid medium into said discharge nozzle to augment the flow of the powdery material therethrough, and said last-mentioned means includes a conduit having an end remote from said discharge nozzle in fluid communication with the container body interior.

7. The apparatus as defined in claim 1 wherein said outlet opening is in fluid communication with a discharge nozzle disposed exteriorly of said container body, means are pro vided for introducing a pressurized fluid medium into said discharge nozzle to augment the flow of the powdery material therethrough, and additional valve means positioned between said outlet opening and said nozzle for selectively opening and closing fluid communication therebetween.

8. The apparatus as defined in claim I wherein said outlet opening is in fluid communication with a discharge nozzle disposed exteriorly of said container body, means are pro vided for introducing a pressurized fluid medium into said discharge nozzle to augment the flow of the powdery material therethrough, said last-mentioned means including a conduit having an end remote from said discharge nozzle in fluid communication with said container body interior, another end of said conduit opening into said discharge nozzle, and additional valve means upstream of said another cond"" nd for selectively opening and closing fluid communication between said container body interior and said discharge nozzle, 

1. Apparatus for discharging powdery material from a container comprising a container body having a bottom wall and an end wall in upstanding relationship thereto, said end wall having an outlet opening through which powdery material is adapted to be discharged from an interior of said container body, said bottom wall having an inlet opening adjacent and upstream of said outlet opening for introducing a pressurized gaseous medium into said container body interior for aerating said powdery material, gravity actuated reciprocal poppet valve means including a valve element having a valve head by which said inlet opening normally remains closed for selectively placing said inlet opening in fluid communication with the container body interior and fluid pressure means for displacing said valve head above said bottom wall whereby powdery material above said valve head is displaced vertically in order to break down any caking that may be present and following which displacement of powdery material the material so displaced and surrounding the valve opening is aerated by the gaseous medium to enable discharge of the material through the outlet opening.
 2. The apparatus as defined in claim 1 including additional valve means for selectively opening and closing said outlet opening.
 3. The apparatus as defined in claim 1 wherein said valve head is movable relative to a valve seat for opening and closing said inlet opening, and means for adjustably limiting the opening movement of said valve head in a direction away from said valve seat whereby the open area between said valve head and valve seat is relatively small in relationship to the area of said inlet opening.
 4. The apparatus as defined in claim 1 wherein the distance between the center line of the valve means and the discharge outlet does not exceed 24 inches in container bodies of up to 1, 000 cubic foot capacity.
 5. The apparatus as defined in claim 1 wherein said outlet opening is in fluid communication with a discharge nozzle disposed exteriorly of said container body, and means are provided for introducing a pressurized fluid medium into said discharge nozzle to augment the flow of the powdery material therethrough.
 6. The apparatus as defined in claim 1 wherein said outlet opening is in fluid communication with a discharge nozzle disposed exteriorly of said container body, means for introducing a pressurized fluid medium into said discharge nozzle to augment the flow of the powdery material therethrough, and said last-mentioned means includes a conduit having an end remote from said discharge nozzle in fluid communication with the container body interior.
 7. The apparatus as defined in claim 1 wherein said outlet opening is in fluid communication with a discharge nozzle disposed exteriorly of said container body, means are provided for introducing a pressurized fluid medium into said discharge nozzle to augment the flow of the powdery material therethrough, and additional valve means positioned between said outlet opening and said nozzle for selectively opening and closing fluid communication therebetween.
 8. The apparatus as defined in claim 1 wherein said outlet opening is in fluid communication with a discharge nozzle disposed exteriorly of said container body, means are provided for introducing a pressurized fluid medium into said discharge nozzle to augment the flow of the powdery material therethrough, said last-mentioned means including a conduit having an end remote from said discharge nozzle in fluid communication with said container body interior, another end of said conduit opening into said discharge nozzle, and additional valve means upstream of said another conduit end for selectively opening and closing fluid communication between said container body interior and said discharge nozzle. 